A wireless communication network represented by the Institute of Electrical and Electronics Engineers (IEEE) standard 802.11 or 802.15.4 typically includes a wireless communication device as an access point (hereafter, “control device”) and a plurality of wireless communication devices as stations (hereafter, “terminal devices”).
In such a wireless communication network, for example, in home network use, a network may be posited in which a communication scheme of an 802.11 standard and a communication scheme of an 802.15.4 standard coexist. For example, a computer and an audio-visual (AV) device such as a television communicate by using the 802.11 standard, and major appliances such as an air conditioner and refrigerator communicate by using the 802.15.4 standard. Further, other wireless networks may be posited in which an older communication scheme of a previously-released product coexists with a new communication scheme of a latest-model product.
In such wireless networks it is preferable from a cost, operation, and maintenance perspective that the number of installed control devices does not increase in proportion to the number of communication schemes, but that, as illustrated in FIG. 15, a single installed control device supports all communication schemes.
However, because a control device 208 does not know when a frame will be transmitted from a terminal device 202a, 202b of a communication scheme A or a terminal device 209a, 209b of a communication scheme B, the control device 208 is required to be constantly, simultaneously, on standby to receive data of different communication schemes.
To solve such a problem, Patent Literature 1 discloses technology which uses shared synchronization signals to receive data of difference communication schemes.
FIG. 16 is a diagram of a network in which a control device 225 communicates with a terminal device 226a using the communication scheme A and communicates with a terminal device 226b using the communication scheme B. A frame transmitted by the terminal device 226a includes a synchronization signal 1, a header 1, and a payload 1, while a frame transmitted by the terminal device 226b includes the synchronization signal 1, the header 1, a synchronization signal 2, a header 2, and a payload 2. Here, for example, a synchronization signal is a physical layer convergence protocol (PLCP) preamble, a header is a PLCP header, and a payload is a PLCP service data unit (PSDU).
Frames transmitted by the terminal device 226b always have the synchronization signal 1 and the header 1 of the communication scheme A attached to a head frame thereof. In other words, according to the technology disclosed in Patent Literature 1, although communication schemes are different, frames have the synchronization signal 1 and the header 1 in common. The header 1 includes information regarding data that follows the header 1. Thus, the control device 225 is constantly on standby to receive a signal of data of the communication scheme A, and performs synchronization judgment using the synchronization signal 1 of receive data. Then, by analyzing the header 1 corresponding to the communication scheme A, the control device 225 is able to judge whether receive data is of the communication scheme A or the communication scheme B.